20 
BULLETIN 1064, TJ. S. DEPARTMENT OF AGRICULTURE. 
Tables 2 and 3 results are given from a set of chips obtained at the 
last streak cut and a set of increment borings made 2 to 3 inches to 
the side of the face at the height of the last streak. The borings, in 
general, showed less effect from the turpentining than the chips, indi- 
cating that the response to the wound was not as marked tangentially 
or circumferentially as it was vertically. The double and the stand- 
ard both showed more reduction in wood formation than the narrow, 
as indicated by ring width. Judged by the borings alone, the double 
showed slightly greater reduction than the standard. The chips, on 
the other hand, showed more reduction in ring width in the standard 
than in the double. This tendency, however, did not hold for the 
u 
n 
1£T£ 
. , 
?o- 
^i. 
. 
>rj_ 
i?" 
? 
i* 
»■»■ 
/&£ 
U.1 
£ 
T 15 
*c 
L - 
o - 
TfitE^d 
/o 
E 
~75 
/9 
'fi 
>>v 
*-~13"* 
"-■». / 
/^ 
"""■ 
V 
n 
J ", 
«« 
^■^Hi 
^_ 
!2«*- 
:zt 
" ~Y 
Trbe- 3 
I 
/ 
\ 
/c 
c 
M 
N 
h<^ 
T 
'V 
q 
— - 
h 
„1. 
-A 
r- !S= T 
»-. <*> 
^.Tn 
fe 
zd. 
£ 
.v 
J=* 
< 
LI* 
^s 
c _ 
TR£T£:2L 
£0 - 
3-^3- 
^ 
s 
^ 
5 
m 
A' 
5 
3 
--: 
^> 
■** 
^ 
i=? 
-M 
- 
-5E 
Trfe / 
^ = 
■ — .e 
«*=■- 
/o 
o 
1 
.— 
&- 
TT 

H!iiir@^5S5ss33gs^3 
Mar. Apr May June Ju/y Aug. 5<zpr. Oct. Nov. Mor Apr. Afoy June Ju/y dug. *5apr Ocr. A/or. 
Fig. 4. — Double trees, 1917. 
Number of tracheids, observed March to 
November ; in 1917, growth ring. ° Sum- 
mer wood present. 
Number of resin centers per unit area 
(an arbitrary tangential extent ; diameter 
o£ microscopic field by the width of the 
annual ring observed). Observed March to 
November, 1917; in 1915, 1916, and 1917, 
growth rings. 
amount of summer wood present, which was exceptionally reduced 
in the specimens from the double tract. It would appear that the 
double chipping produced a special response which vvas manifest in 
the increased ring width shown by the chip specimens and in the 
sustained relatively high yield for the second year, which has been 
mentioned. It would seem, however, that this response was accom- 
polished at the expense of summerwood production and of the tree's 
vitality in general, judging by such indications as these and by the 
frequent occurrence of " dry " faces in this crop. The double also 
produced fewer resin passages than the narrow. In 1917 (Table 4) 
the reduction in wood formation in the specimens collected from 50 
